1. Field of the Invention
The invention relates in general to the interconnection of a fusible link and an electrical relay on a vehicle electrical junction block, and more specifically to an arrangement wherein the relay is electrically connected directly to the fusible link through a top of a housing containing the fusible link.
2. Discussion of Related Art
A typical power distribution box or electrical junction block as used in automotive vehicles eliminates multi-branch wiring by consolidating electrical components such as relays, fuses and connectors in a single location. A surface of the junction block has a plurality of slots forming footprints for receiving male contact blades of electromagnetic relays or other types of relays or switches, receptacles for receiving fuses or fuse cartridges, and other accommodations for electrical modules and connectors.
As illustrated in FIGS. 1 and 2, relays and fuses are usually electrically connected together by a stamped bus bar 20 with upstanding male end tabs 22 incorporated under the junction block surface. A rectangular fusible link housing 24 has a solid cover 26 and a slotted underside 28. Female terminals 30 are positioned within the housing 24 adjacent the underside 28 and connected by a fusible link 34. At one location on the junction block, a male tab 22 at one end of the bus bar 20 is received through the underside 28 of the housing 24 into engagement with one of the female terminals 30. The other female terminal of the fuse would receive, for example, a male contact of a power supply bus within the junction block. At another location in the junction block, a separate female-to-female terminal 36 is used to electrically connect a male contact blade 38 of a relay 40 with the other male end tab 22 of the bus bar 20. In other words, to complete the electrical interconnection of the fuse and relay, two extra parts, a female-to-female terminal 36 and a bus bar 20, are required. This creates additional electrical resistance in the circuitry and adds cost to the system.
As vehicle electrical systems become more complex and require more electrical components and extensive circuitry, there is design pressure to increase the size of the junction block. However, vehicle manufacturers often want the junction block to take up as small a space as possible within the vehicle. There have been attempts over the years to provide more efficient, interchangeable, compact packaging space on the junction block surface. For example, in U.S. Pat. No. 6,089,918, an adapter is used to enable fuses to plug into footprints originally meant for an electrical relay. This does not address the issue of more efficiently interconnecting a relay and fuse. It is also known in the art, for example from U.S. Pat. No. 6,320,486, to incorporate a fuse into a relay casing. This presents a bulkier relay and limits the ability of the fuse to be connected to other electrical circuitry.